5-epi-Incensole: synthesis, X-ray crystal structure and absolute configuration by means of ECD and VCD studies in solution and solid state

Incensole 1 and its acetate 2, found in incense, demonstrate interesting biological activities. Incensole acetate 2 was prepared on a large scale by employing the Paul and Jauch protocol from the crude extracts of Boswellia papyrifera Hochst. 5-epi-Incensole 3, obtained as colorless crystals, was prepared from incensole acetate via three steps; deacetylation, oxidation and reduction. The structure of 5-epi-incensole 3 was elucidated by means of spectroscopic data analysis, and the absolute configuration was established by single crystal X-ray analysis in combination with electronic and vibrational circular dichroism. In particular, the applicability of the solid-state ECD/TDDFT protocol to a compound with only two non-conjugated alkene chromophores was verified

Recent Advances in the Stereoselective Total Synthesis of Natural Pyranones Having Long Side Chains

Pyranone natural products have attracted great attention in recent years from chemists and biologists due to their fascinating stereoisomeric structural features and impressive bioactivities. A large number of stereoselective total syntheses of these compounds have been described in the literature. The natural pyranones with long side chains have recently received significant importance in the synthetic field. In the present article, we aim to review the modern progress of the stereoselective total syntheses of these natural pyranones containing long-chain substituents

Efficient organocatalytic multicomponent synthesis of (α-aminoalkyl)phosphonates

l-Proline has been used as an organocatalyst for an efficient synthesis of (α-aminoalkyl) phosphonates by treatment of aldehydes, amines and triethyl phosphate at room temperature. The products are formed in excellent yields (82–94%) within 30–45 min

Fig. 2 in Cembranoids from Boswellia species

Fig. 2. Structures of cembranoids of Boswellia species.Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 5, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074

Fig. 4 in Cembranoids from Boswellia species

Fig. 4. Structure of boscartin-A (30).Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 9, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074

Fig. 5 in Cembranoids from Boswellia species

Fig. 5. Structural relationship between cembrenol and incensole.Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 10, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074

Fig. 1 in Cembranoids from Boswellia species

Fig. 1. Structure of cembrene (1).Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 2, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074

Fig. 2 in Cembranoids from Boswellia species

Fig. 2. (continued).Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 6, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074

Fig. 2 in Cembranoids from Boswellia species

Fig. 2. (continued).Published as part of Al-Harrasi, Ahmed, Avula, Satya Kumar, Csuk, René & Das, Biswanath, 2021, Cembranoids from Boswellia species, pp. 1-17 in Phytochemistry (112897) 191 on page 7, DOI: 10.1016/j.phytochem.2021.112897, http://zenodo.org/record/838074